Parker richardson bradley



METHOD 0F DoPf'NG AIRCRAFT. APPLICAUON FILED DEC. 22. 1917.

1,309,454, A Patented my 8, 1919.

mail@ m @may A TTOBNEYS weather.

UNITED srnrns Pn'rnnr ernten@ PARKER RICHARDSON BRADLEY, OF EAST ORANGE,NEW JERSEY, ASSG'NOR T0 AIRCRAFT FIREPROOFING CORPORATION, OF NUTLEY,NEW JERSEY, A. COPU P ORATION OF NEW JERSEY.

'METHOD 0F DOPING AIRCRAFT.

Specification of Letters Patent.

Patented July 55,

Application tiled December 22, 1917. Serial No. 208,448.

To 1H wlw/n, t muy concern.'

Bc it known that I, Pannen R. B'ixnLnY, a citizen of thelhited States,and a resident of East Orange, in the vcountyiof Essex and btate of NewJersey, have invented a new and Improved Method of'Doping Ain craft, ot'which the following is a full, clear, and exact description-.

This invention relates to an improved method Vot' applying dope`ortireproof coating liquid to wing and other surfaces-of flying machines.and the invention has for its general objects to improve the system ofearrying on this work 'so as to'bc economical, expeditious, eliminatewaste and at tlie same time prevent danger of poisoning the employeesfrom noxious fumes or creating a nuisance to the neighborhoodin whichthe plant. is established.l

lVhile an aeroplane is very large and bulky, measuring fortyto seventyfeet and more .from tip to tip of wings, `it is -made up ot' a number ofcomparatively small sections jointed one :to the other with metalattachmente.y These sections areconstrncted of small pieces of wood as aframework over which is stretched linen or other cloth. Ow-A ing togtheshape of the frame it is not possible to stretch the cloth on tightly,thereforea ydope or waterproof coating is used, which as it dries willcontract and draw up the liueix cloth to a tight, drumlike surface.

lt is customary to apply anumber of coat-' ings ofdope, say six to tencoats, and when all are dry to apply one or more coatings of sparvarnish, which stands the weather better than any` dope. 4

lleretofore all this ,work has been done by hapdemployingskilledpainters, and

.each coating is dried in the workrooln, and

takes tive or more hours, depending on the During -the drying, poisonousgases or vapors are given oft' in great volume, which, if alargebusiness is done, invariably causes sickness among the einployees, andsometimes results in the death ot' yemployeev besides being an. offenseto the entire neighborhood; and the aeroplane takes about `ten days forits completion.

The present methods when followed on a large scale have several seriousobjections, such as poisoning the employees; creating a nuisance in theneighborhood; labor dipping frames, submergiiig the frames and aeroplaneparts in a tank containing a dope which is sufficiently liquid topermitof dipping, raising the frames and dipped parts out of the tank,and then conducting them through an air-tight drying chamber w 'ih hassuitable means for drawing oft and condensing the vapor and fumes.Before the sections of the wing are dipped each is provided with a drainopening at the bottom so as to permity the surplus dope to drain olf theinner surface of the fabric.

For a more complete understaiiding` of the invention reference is to behad to the following description and claims taken in connectionwith theaccompanying drawings, in whichsimilar characters of reference indicatecorresponding parts in all the views, and in which Figure i is a plan`View of one of the cars on which the dipped parts hang dering inedipping and drying operation; i

Fig. 2 is a vertical section showing a pire rality of wing sectionssuspended on car and submerged in a deep tank The carriage B on whichthe wing sections are supported while being (lipped or while drying,travels on rails 7 from the dippingl 'station to the drying room, andfrom the latter to a point of discharge. ln' the dipping room are trackrails l2 on which is a tank 13 into which the wing sections are dipped.

The ear B comprises a horizontal car frame 15 having trolley wheels itib which the car is suspended on the track rails. @n the car frame is anelevating fi une lll yembodying corner uprights Nrwhich have rack teeth1S. rl`lie`seteeth mesh with pinions .19 on horizontal cross shafts 20,which latter are connected by gears E21 with a longitudinal shaft 22. Onthe shaft "2 is a .16 will be held raised.

'tank containingthe dope.

4is the lightestweight t'or sockets.

largegear wheel :23 whiehnieshes with a pinion il on a transverseoperating shat't 25 that carries a brake wheel '.'i with which cngages abrake band or equivalent means 27 which normally is frictionally engagedwith the brakewheel so that the elevatin frame ()n the en( ot the shat't25 is a clutch element 28 which is adapted toA engage with a clutchelement 2t on a power shat't 30 located in the tankroom 2. The shaftil() is moved longitudiually to engage oi'disengage the clutch elementsand 2S) when a car B is in proper position over the dipping tank. 'henso positioned the brake band ,slightly released, so that the elevatingt'ranie can be lowered to subiiierge the parts to be coated in the tank.and after theI lapse o'l a proper Vpei'iod ot time the power may beapplied to the sha t't` either by hand or motorrto gradually raise theelevating trame and i'emove the coated parts l'rom the tank. lVhen Itheelevating frame lo -is t'ully raised the brake device is set and theclutch element .29 disengaged t'rom the clutch element 28, so that thecar with the coated parts thereon can he moved into the' oven. Dippingtrames ill are employed to support the aeroplane wing sections and theother parts that are to be coated, these frames being attached bysuitable connecting devices 32 to the elevating frame 16. rlhe meanst'or attaching the aeroplane parts to the dipping trames are not shown,as any suitable, devices mayy be employed.

The. operation is as l'ollows:

'lhe dipping frame loaded with-aeroplane parts is placed indipping'rooiii over the 'l`he power is started andthe dipping tramelowers the aeroplane parts into the tank at the greatest speed possiblewithout splashing and they Aremain a l'ew moments; they are then raisedvery slowly indeed. completely out of tank and'allowed to drain a t'ewmoments. rI`he total time consumed in applying one coat to an aeroplane.should lie about fifteen ininutes, divided as follows: one minute toeriter; three minutes to soak: six minutes to withdraw: tlve minutes todrain. The door tothe drying room 4is then opened and the car with thedipping trame and contents enters oven and the dooi' is closed. llt maytak a longer or a shorter period ol' time.

The lowest. parts of the aeroplane sections are to have drain holes .rbored through the wood trames, with metal sockets; aluminum Thesesockets prevent the weakening of the Jframe. The first coat ot' dopesoaks through, coating the back ot' the fabri' as nuich as the tace andthereby obtaining a' t'ar superior ett'ecty thanl is obtained ,bybrushing on the dope by hand or any other way. `Otl course the dopeinside the aeroplane frames must be A p moved into drying oven and thevapors arising from the dry'ing process are condensed into solvents. ltrequires about an hour to dry. this period will be iiioi'e or lessaccording to the boiling points otI the solvents used and the heat ofthe drying ovens. 'ith air locks and a partial vacuum in the dryingovens a solvent may be used ot a very low boiling point. whereas whenthe work is done by hand, as is now the invariable custom. 'in the openair ot' the ordinary work-v shop. a lai'ge proportion of high boilingpoint solvent must be used to oll'sct the daiiipness in the air. This isa very iiiipoi'- tanti point. as low boiling solvents are usually t'ai'cheaper than the high boiling solvents .ind are not ol" such anobnoxious odoi' and are not as poisonous.

'hen the surface ot' thecloth on wings is dope-tight` say after first orsecond dipping. the drain holes should be plugged with corks or plugs.as no further drainage is needed, as the dope will have ceased soakingthrough thil cloth. titer the desired number of coatings ot' dope havebeen applied. the dope tanh is replaced willi a tank ol' spar vai'- nishand the door between the drying oven aml dipping i'ooiii is opened sothe temperatiii'e ol the dipping room is raised to ai'oiiiid Utl"ahrenheit, more orI less, and the doped t'rames are dipped into thespar varnish. The varnish and room must be warm and the dipping is donevery slowly. taking at least twenty minutes and the ordinary commercialspar varnish may be thinned down with turpentine. A\tter the coating ot'spar 'an nish has been applied the. car is moved into the drying rooma-iid dried two hours and then moved into open air of workshop.

rlhe solvents are condensed but are drawn ofi' into separat/e barrelsfrom those containing dope solvents. 'lhc varnish requires six lioui'sto dry sutlicieiitly so the wings may be removed Vt'rom dipping trameand hung up in storage lot'ts.

llaving thus described my invention. l claim as new and desire to secureby'Lette'rs lateut l. The method of doping a hollow aeroplane wingsection having at'abric-covered lrame with drain openings in thetrame,which consists in dippingthe said section in a coating material longenough to permit the coating material to penetrate through the pores ofthe fabric, draining the surplus material from the outer and innersurfaces of the wing section, drying the coating inateriah and repeatingthe dippit'if, draining and drying steps a plurality of times.

2. The method ot' doping a hollow aeroi plane wing provided with drainnieanst'or tlw ('lxzmlbei of the wing. which consista in supportnngr lwwlng 1n position with the drum imams :it rlw'lmttom and dipping thewingr thus supported in n mmtinglf liquid, 1'0- nlovingf the win,f rfrom the liquid, Supporting' tlm wingr whereby the sui-plus llqxud candrip Oil" the outer surface of the wing and drain 'ont die drain meansof the vlnnnbm'. closing' the drain nionnfs, und repeating' the dipping'and draining operation, wlwi'oby only the outer surfaces of the wingwill receive :mother coating?.

PARKER RICHARDSON BRADLEY.

